I’ve discussed this subject before, and I’m pleased to say the answer is the same as it’s always been: there’s no safe upper limit. The latest study on coffee and mortality is very large (more than 400,000 participants), with long-term follow-up (more than 30 years), and finds that those who drink more caffeinated beverages live longer — meaning coffee, tea, caffeinated soft drinks — doesn’t matter.

Note they’re not wearing bibs at Starbucks now; their death rate was about 10% lower for men and women drinking one or two cups per day (compared to those who don’t drink it at all). Those drinking 3-5 cups saw about a 15% reduction in mortality risk. And those with more than 5 cups per day saw a 20% lower risk.

How about decaf? No significant reduction, although the sample size is small (only about 22,000). But regular coffee drinkers didn’t see any increase in mortality with an “high” intake of 8 or more cups per day either. So who knows what’s going on there, but probably nothing to worry about even if you drink that much coffee. Again, this is all caffeinated beverages; tea and soft drinks were not included in this study.

What do we know already? A 2012 meta-analysis found that drinking two or three cups of coffee per day was associated with a significantly reduced risk of dying from heart disease (23%), cancer (10%) and diabetes (50%).

A 2011 study reported that drinking coffee reduced the risk of heart failure.

Earlier this summer, a study found that three to five cups of coffee per day was associated with lower inflammation markers in postmenopausal women.

How does it work? Coffee has many chemicals that may confer health benefits, including antioxidants and anti-inflammatory compounds. But there are so many variables involved — different beans, preparation methods, individual reactions — it’s not clear how these positive effects come about or if they’re all clinically relevant for any one person.

Note also coffee contains caffeine, which can be deadly in high doses but is still an incredibly popular drug despite its risks.

So I’ll say it again: don’t worry about how much you drink. If you like coffee, it’s not going to hurt you (unless you keep chugging that super-caffeinated Monster Energy Drink all day long).

And don’t be surprised if I write about the latest study in about 20 years and find that drinking more than 5 cups per day is associated with reduced mortality.

As usual, I’m not getting anything from writing this post; no one pays me to blog here. Just promoting good science! And sometimes I even do that for free…

A single 24-hour dietary recall provides a very limited amount of information about past intakes and does not reflect usual intake over longer periods of time as can be obtained from multiple recalls or food records. As such, the results from this study must be viewed as tentative and one should not draw causal conclusions without further research. I’d like to see a study using food records or multiple 24-hour recalls; it would be helpful for those who are interested in the dietary habits of older adults and for researchers who need accurate information about what people typically eat over time.

One last thing: as others have pointed out, this paper does not support heavy coffee drinking as a healthful behavior. The results show that those who drank more coffee were less likely to die, but do not reveal whether they developed costly chronic diseases such as heart disease or diabetes later in life requiring expensive medical care and increasing the likelihood of early death from these conditions (as has been suggested by some other studies).: Here’s another perspective: “The study by Freedman et al. (1) suggests that coffee drinking might protect against total and cause-specific mortality. However, it is not possible to determine whether this would be because of a causal effect of coffee, an effect of residual confounding, or both.”

Here are some signs that you’re drinking too much coffee.

1. You drink a little coffee every hour all day long.

2. You can’t go to sleep until you’ve had your caffeine fix for the day.

3. You have withdrawal symptoms if you don’t get your daily dose of caffeine (headache, irritability, etc.).

4. When you haven’t had coffee for a while and then have some, it doesn’t give you the boost you’re used to getting from it because your body has developed a tolerance to the stimulant properties of caffeine over time.

5. You are drinking caffeinated beverages when pregnant or trying to become pregnant, when breastfeeding or when giving formula to your baby that contains caffeine.

6. You’re using coffee to stay awake while driving long distances when you should be taking regular breaks for rest and relaxation during your trip.

7. You feel anxious or jittery after drinking caffeinated beverages, especially if you don’t normally drink caffeine on a regular basis.

8. You can’t get the day started until the pot of coffee is ready in the morning.</be>

9. Your doctor has told you to cut down on your caffeine intake because he/she thinks it’s bad for your health.<be>

10. You keep trying out new “healthy” ways of making coffee at home, like using soy milk instead of dairy milk, but you’re still hooked on all that sugar and cream.

While caffeine generally does not cause addiction, dependence, and withdrawal symptoms in healthy adults, it can become a problem for some people. Research has linked the following symptoms to caffeinated beverages: anxiety, nervousness, restlessness, irritability, or even panic attacks. If you suffer from these symptoms all the time and they don’t go away after quitting coffee (and possibly other drinks containing caffeine), you may want to see your doctor about getting an evaluation for caffeine-dependency syndrome.

According to the researchers of the study published Wednesday in JAMA Internal Medicine, older adults who drank three cups of coffee per day were 18 percent less likely to die during a 10-year follow-up period than those who didn’t drink coffee at all or drank just one cup.

The study did not determine why coffee was associated with longevity, but the lead author, Dr. Erikka Loftfield of the National Cancer Institute in Rockville, Md., speculated that the antioxidants in coffee may reduce inflammation throughout the body and protect cells from damage by harmful molecules called free radicals.””Coffee is also rich in magnesium,” Loftfield said. “Other research has suggested that magnesium may lower the risk for type 2 diabetes.”

“I think it’s great news because people are always trying to find out how to increase their longevity,” says Dr. Donald Hensrud, director of preventive medicine at Mayo Clinic. He was not involved in this study.